Speaking of the
sear, exactly how does a trigger work? As you might have guessed, that is a
function of the trigger design. In the case of a bolt action, the trigger
serves to release the firing pin housed in the bolt. The surfaces that control
the release of the firing pin are called the trigger sear. On a Winchester
Model 70 trigger, the trigger itself engages the firing pin. This makes for a
simple trigger, but this design has drawbacks. It is difficult to obtain a
light trigger pull that is creep-free – there is too much friction. The
Remington trigger, which first came out in 1948, uses a lever between the firing
pin and trigger to eliminate the friction problem. Figure 1 illustrates the
basic design of this trigger, which has been copied by many other suppliers. A
Timney trigger, for example, is almost an exact replica of the Remington (but of
higher quality). Essentially, the middle lever contains a square edge that
bears against another square edge that is part of the curved trigger. When a
shooter pulls on the trigger, it causes the square edge to move forward, which
in turn causes the opposing square edge on the middle lever to become
unsupported. Because the opposite side of the middle lever has an angled
surface that bears against another angled surface on the firing pin, the lack of
support of the middle lever causes it to fall and the firing pin to move forward.
Figure 1 – The Remington
700/Model 7 Trigger
The pressure
required to break a Remington trigger is a function of the weight of pull and
the trigger sear engagement, or the amount of engagement between the two square
surfaces. If you look carefully at Photograph #1, you can see the two surfaces
(look at the hole in the trigger housing just below the receiver cut for the
bolt handle). Both the sear engagement and the weight of pull can be adjusted,
as can the amount the trigger moves after the trigger release, also called
backlash. Photograph #2 shows the front of the trigger housing; the two screws
in the photo are used to adjust the weight of pull and the amount of backlash.
Photograph #3 shows the backside of the trigger housing, which contains one
screw used to adjust the sear engagement.
Of course, the
first step in adjusting the trigger is to remove the barreled action. On
actions that have a floorplate, this is accomplished by removing the two screws
on the trigger; on the ADL model there is a trigger guard retaining screw that
must also be removed. Following removal of the screws, simply pull the action
out of the stock. On an ADL model, you must remove a magazine box retaining
screw; on the BDL version, this can simply be pulled away. If you examine the
trigger housing, you will see that the screws on the trigger housing are covered
with a shellac-looking substance that prevents movement of the adjustment
screws. This substance must be removed before adjusting the trigger screws; a
sharp knife or razor blade is best for this. The back screw, the sear
adjustment screw, is the most difficult to clean, but if you don’t do this, you
will ding up the screw head. Now let’s discuss exactly how to adjust the
trigger.
